18978992 has 20 divisors (see below), whose sum is σ = 38040720. Its totient is φ = 9162048.

The previous prime is 18978989. The next prime is 18979003. The reversal of 18978992 is 29987981.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19988 + ... + 20915.

It is an arithmetic number, because the mean of its divisors is an integer number (1902036).

Almost surely, 2^18978992 is an apocalyptic number.

It is an amenable number.

18978992 is an abundant number, since it is smaller than the sum of its proper divisors (19061728).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18978992 is a wasteful number, since it uses less digits than its factorization.

18978992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40940 (or 40934 counting only the distinct ones).

The product of its digits is 653184, while the sum is 53.

The square root of 18978992 is about 4356.4884941889. The cubic root of 18978992 is about 266.7417816173.

The spelling of 18978992 in words is "eighteen million, nine hundred seventy-eight thousand, nine hundred ninety-two".